From: Alex Williamson alex.williamson@redhat.com
commit 07956b6269d3ed05d854233d5bb776dca91751dd upstream.
follow_pfn() doesn't make sure that we're using the correct page protections, get the pte with follow_pte() so that we can test protections and get the pfn from the pte.
Fixes: 5cbf3264bc71 ("vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn()") Reviewed-by: Jason Gunthorpe jgg@nvidia.com Reviewed-by: Cornelia Huck cohuck@redhat.com Reviewed-by: Peter Xu peterx@redhat.com Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vfio/vfio_iommu_type1.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -24,6 +24,7 @@ #include <linux/compat.h> #include <linux/device.h> #include <linux/fs.h> +#include <linux/highmem.h> #include <linux/iommu.h> #include <linux/module.h> #include <linux/mm.h> @@ -431,9 +432,11 @@ static int follow_fault_pfn(struct vm_ar unsigned long vaddr, unsigned long *pfn, bool write_fault) { + pte_t *ptep; + spinlock_t *ptl; int ret;
- ret = follow_pfn(vma, vaddr, pfn); + ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl); if (ret) { bool unlocked = false;
@@ -447,9 +450,17 @@ static int follow_fault_pfn(struct vm_ar if (ret) return ret;
- ret = follow_pfn(vma, vaddr, pfn); + ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl); + if (ret) + return ret; }
+ if (write_fault && !pte_write(*ptep)) + ret = -EFAULT; + else + *pfn = pte_pfn(*ptep); + + pte_unmap_unlock(ptep, ptl); return ret; }